<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // // 数字直接存储
        let age = '5'
        // // 字符用单引号引起来，表示一段信息  
        // let name = '丁晓豆'
        // document.write(age)
        // console.log(name);

        // 3、更新变量
        // let uage = 10
        // 变量里面的数据发生变化更改为5
        // uage = 5
        // 页面输出的结果为5
        // document.write(uage)

        // let uname = '丁'
        // let uname ='豆'

        // 交换变量的值 
        let orange = '橙子汁'
        let apple = '苹果汁'
        let temp
        document.write(orange +'<br>')
        document.write(apple + '<br><br>')

        temp = orange
        orange = apple
        apple = temp

        document.write(orange +'<br>')
        document.write(apple + '<br>')

        let uname ='丁'
        let Uname ='丁'

        
    </script>
</body>
</html>